Question

Weight of 30 students of a class at the time of medical test is recorded as per table given below

Weight (in kg)	40-45	45-50	50-55	55-60	60-65	65-70	70-75
No. of students	2	3	8	6	6	3	2

Find mean weight of students.

Answer 1

Let assumed mean (A) = 57.5

Arithmetic mean (\(\overline { x }\)) = A + \(\frac { { \Sigma f }_{ i }{ d }_{ i } }{ { \Sigma f }_{ i } } \) = 57.5 + \(\frac { -10 }{ 30 }\) 

= 57.167 = 57.17 kg.

Thus, mean weight of students 

= 57.17 kg.